1. Field of the Invention
The present invention relates to a method and an adapter connected to an IMS/MMD (IP Multimedia Subsystem/Multimedia Domain) network.
2. Description of the Related Art
3GPP2 (3rd Generation Partnership Project 2, the standard of a third-generation mobile phone system) or 3GPP standardizes an IMS/MMD platform to make a mobile communication network ALL-IP. The IMS/MMD platform (hereinafter called “ALL-IP core network”) uses IPv6 technology. This is an important base technology in the next generation network (NGN: Next Generation Network). According to J. Rosenberg et al., “SIP: Session Initiation Protocol”, IETF RFC3261, June, 2002, the ALL-IP core network uses SIP (Session Initiation Protocol) for communication control of multimedia data including voice data.
According to SIP, position information of a client (e.g., a mobile terminal) is registered in a registrar server. The SIP proxy server connects these clients by using the registration information.
Actually, the ALL-IP core network incorporates an authentication/encrypting protocol such as IMS-AKA (IP Multimedia Subsystem/Authentication and Key Agreement) into basic SIP. An IPv6 client having a SIP enhanced function of 3GPP or 3GPP2 can connect with the ALL-IP core network directly.
However, many existing clients such as a portable telephone do not comprise a protocol stack of IPv6. Also, these clients cannot process an encrypting protocol which requires high computing power. Thus, even if these clients comprise a SIP function, they cannot execute a registration authentication sequence for the registrar server connected to the ALL-IP core network. Such a problem disturbs early conversion to IMS/MMD.